This study proposes to determine optimal management of mild hypertensive patients by evaluating physiological and behavioral components that are important from a personal health and public welfare viewpoint, including blood pressure change, side effects, change in associated risk factors, and change in psychological and behavioral variables. In order to achieve this goal, three dietary components (1 - no dietary change; 2 - weight loss; 3 - decreased sodium, increased potassium) and three drug regimens (1 - placebo, 2 - thiazide diuretic and 3 - beta blocker) will be evaluated through a 3 x 3 factorial design. Nine hundred and eighteen (918) mild to moderate untreated hypertensive individuals, age 25 to 65 years, 110-150 per cent ideal weight without major end-organ damage, and with sitting diastolic blood pressures (DBP) between 90-100 will be enrolled in three clinical centers (Albert Einstein College of Medicine, The Bronx, New York; University of Alabama at Birmingham Medical School; and the University of Mississippi Medical Center at Jackson). The Coordinating Center will be at the University of Texas School of Public Hedalth in Houston. Biochemical and psychological variables will be determined at baseline, and at appropriate intervals. The major outcome variable will be blood pressure change at six months. Further aims are to determine changes in cardiovascular risk and in psychological functioning and life style. At six months, individuals who have not reached their goal diastolic blood pressures will have a step-up therapy utilizing an antihypertensive drug. All patients will be followed for a minimum of twelve months and a maximum of thirty months in total. The long-term efficacy of drug diet treatment patterns will be assessed in addition to the primary evaluation described above. Planning will occupy the first six months and induction the next eighteen months. Transition and close-out will be completed during the fourth year, and the remainder of the fourth year will be analyses and publication.